Table 2.
scan and reconstruction parameters
| Parameters | gCCT | ngCCT |
| Scan parameters | ||
| Technique | Spiral | Spiral |
| kV | 120 | 120 |
| mAs | 150 | 30 |
| Gantry rotation time (ms) | 330 | 330 |
| Individual detector width (mm) | 1.2 | 0.6 |
| Number of detectors | 20 × 2 | 32 × 2 |
| ECG gating | Yes | No |
| Prospective ECG modulation of tube current | Yes | No |
| Table feed/s (mm) | 14.4 | 86.4 |
| Pitch | 0.2 | 1.5 |
| Scan range | Carina-Apex | Chest |
| DLP (mGy; mean ± SD) | 116 ± 51 | 84 ± 16a |
| Effective dose (mSv; factor = 0.014; mean ± SD) | 2.0 ± 0.9 | 1.2 ± 0.5a |
| Effective dose (mSv; factor = 0.014; median, IQR) | 1.61; 1.15-2.0 | 1.13; 1.05-1.20a |
| Reconstruction parameters | ||
| Effective slice width (mm) | 3.0 | 5.0 |
| Reconstruction increment (mm) | 1.5 | 5.0 |
| FOV (mm) | 140-160 | 250-300 |
| Kernel filtering | B35f1 | B30f(medium-smooth) |
The Table shows the scan parameters for gCCT and ngCCT. gCCT vs ngCCT,
a
P < 0.05;
1
Dedicated filter for calcium scoring. gCCT: ECG gated cardiac computed tomography; ngCCT: Non-gated chest computed tomography; FOV: Field of view; ECG: Electrocardiogram; DLP: Dose length product.